Referring to FIGS. 1 and 2, a prior art reverse osmosis pressurized cylinder is illustrated. The pressurized cylinder is formed by an upper cover 11, a lower seat 12, a buckling ring 13 and an inflation isolating film 14.
The upper cover 11 and lower seat 12 are made of plastics or metals. The interiors of the upper cover 11 and lower seat 12 are concave. An openings of the upper cover 11 and lower seat 12 are formed with flanges 111, 121. A top of the upper cover 11 is formed with a water inlet 112 for be connected to the water inlet valve (not shown). An inner side near the opening of the upper cover 11 has a concave wedge surface 113.
A lower end of the lower seat 12 is installed with an air inflation mouth 122 for assembling an air inflation valve. An edge of the opening of the lower seat 12 is flat.
The buckling ring 13 is a T shape cross section. Before combining the upper cover 11 and lower seat 12, an flange 131 of the buckling ring 13 and the lower end 141 of the inflation isolating film 14 are placed on the concave wedge surface 113 of the upper cover 11.
Thereby, when the lower seat 12 is aligned to the upper cover 11, after high speed rotation and compressing, the two are melt so as to combine as an integral body. Then the buckling ring 13 and the inflation isolating film 14 are embedded into the upper cover 11 and lower seat 12. Thus the interior of the pressurized cylinder is divided into a water storage chamber I and an air inflation chamber II. The lower seat 12 is connected to the air inflation valve for inflating air into the air inflation chamber II so that the air inflation chamber II has a predetermined pressure. When external pressure of the water inlet valve is larger than the interior pressure of the air inflation chamber II, the water inlet valve will guide water into the water storage chamber I. The inflation isolating film 14 is pressed downward so that the volume of the air inflation chamber II is reduced. When a user opens a faucet, the pressure of the water inlet valve is reduced, and the inflation isolating film 14 is ejected upwards due to the pressure of the air inflation chamber II. Thereby, water can flow out so as to achieve the objects of storing water and outputting water by pressure.
Above mentioned prior art has the following defects:
The buckling ring is necessary so as to increase cost in material and manufacturing.
The buckling ring 13 can not retain in a tight contact with the inflation isolating film 14 when the upper cover 11 is coupled to the lower seat 12. Thereby, water and air possibly drain out.
When water in the reverse osmosis pressurized cylinder is in full level, the air inflation chamber II below the inflation isolating film 14 has a larger pressure. Thereby, air in the air inflation chamber II possibly vents out so that the pressure of the air inflation chamber II is insufficient. Thereby, the air inflation chamber II must be inflated through an air inflation hole 122 when the reverse osmosis pressurized cylinder is used for a long time so as to retain the pressure in a predetermined value.
In the reverse osmosis pressurized cylinder, the upper cover 11 and lower seat 12 are combined by an un-detached way. Therefore, it is impossible to clean and maintain the pressurized cylinder and to update the parts of the pressurized cylinder.
Moreover, to reduce water hammer in the high pressure pipeline, a pressure-stable cylinder is provided, which has the function of buffering and stabling water. Referring to FIG. 3, in general, the pressure-stable cylinder is installed at the pipeline or a lower side of the pipeline. A through hole of the pressure-stable cylinder is connected to the pipeline. The buffering effect of the pressure-stable cylinder can prevent water hammer. The structure of the pressure-stable cylinder is approximately identical to that of the reverse osmosis pressurized cylinder. The difference of the two is that the through hole of the pressure-stable cylinder is larger than water inlet of the reverse osmosis pressurized cylinder, and thus the pressure of the air inflation chamber is larger than that of the reverse osmosis pressurized cylinder.
The pressure-stable cylinder a includes an outer cylinder 1a with a through hole a10 at a top thereof. The through hole a10 is connected to a water inlet tube b and a water outlet tube c. The outer cylinder 1a has an upper groove a11 and an upper flange a12.
A film a2 is made of elastic plastic material and is placed in the outer cylinder a1. The opening of the film is connected to an inner lateral surface of the outer cylinder a1.
A lower cover a3 has an opening slightly larger than that of the outer cylinder a1. The lower cover a3 has an air inflation mouth a31, a lower groove a32, a lower flange a33 for engaging the outer cylinder a1 and lower cover a3. Thereby, the upper flange a12 is buckled to the lower groove a32 and the lower flange a33 is buckled to the outer cylinder a1, as shown in FIGS. 4 and 5.
In this prior art pressure-stable cylinder, since many parts are used, which are made singly so that air easily drains out so that the function of buffering water pressure is lost. Thereby, the pressure-stable cylinder is made of metal. If it is used for a long time, it easily rusts so that the air pressure is insufficient and thus the buffering function is lost.